1. Field of the Invention
The present invention relates to a power plug assembly, more particularly to a power plug assembly having a function of lighting indication.
2. Description of Related Art
Power plugs are commonly seen and used in daily life and can be categorized to two sorts, a power receiving plug and a power supplying plug, wherein the power receiving plug is often an AC power plug having two or three electrodes for obtaining the public power source; the power supplying plug mostly is a round-column shaped DC power supply, and the outer diameter of the power supplying plug is varied with respect to a diameter of a power socket of an electronic device, e.g. a notebook computer.
As shown in FIG. 1, which is a schematic view of a connection between a cable 10 and a conductive tube 20 of a conventional power supplying plug, the cable 10 includes two power wires 101, 102, respectively having positive electricity and negative electricity; for proving a signal transferring function to the cable 10, the cable 10 can be further provided with a signal wire 103. In order to have the end sections of the wires of the cable 10 connected to the conductive tube 20, the wires respectively having positive electricity and negative electricity are correspondingly welded to the corresponding sections on the conductive tube 20, so an outer tube 201 and an inner tube 202 of the conductive tube 20 are respectively provided with functions of transferring negative electricity and positive electricity, then an operation of embedded-type plastic injection is operated so as to obtain a covering member for covering and packaging the connecting section between the cable 10 and the conductive tube 20, thus a power supplying plug is obtained.
A means commonly used for observing whether a power supplying plug is normally operated is to observe the power supplying status of an electronic goods to which the power supplying plug is inserted, e.g. a charging status shown on a screen of a mobile phone, or a charge indicating lamp of a notebook computer, for observing the operation of the power supplying plug is not convenient. The Taiwan Patent Application No. 097202976, corresponding to the China Patent Application No. 200820007120.4, titled “Power plug assembly”, has disclosed that a printed circuit board is crossly connected to a positive terminal and a negative terminal of a terminal set, the rear end of each of the terminals is provided with a connecting section respectively connected to end sections of power wires of a cable, and the front end of each of the terminals is respectively welded to an outer tube and an inner tube of a conductive tube. A LED is provided on the printed circuit board and the LED can be lit by obtaining the required power via the printed circuit board, and lights illuminated from the LED pass through a transparent inner covering member and a pre-set window provided on an opaque outer covering member, so a user can be informed that the power plug is in a power-supplying status.
The art disclosed by the above mentioned patent application has solved the problems that conventional power plugs are not provided with a function of indicating the current status of the power plug, but only a single light source is adopted for indicating, so an improvement of increasing the illuminating area or increasing illumination for a better identification is needed.